Piston type discharge valve



Jan. 1, 1935. c. A., buNHAM 1,986,429

PISTON TYPE DISCHARGE VALVE Filed June 13, 1932' 2 sheets-sheet 1 Jnl, 1935. c. A. DUNHAM PISTON TYPE DISCHARGE VALVE Filed June 13, 1952 2 Sheets-Sheet 2 Patented Jan. 1,1935

PATENT OFFICE a Hs'rort-:TYPE DISCHARGE vALvE Clayton Dunham, Glencoe, Ill., assignor to C. A.

Dunham Company; poration` of Iowa Marshalltown, Iowa, a corz Application Jeis, 1932",.seria1N0.616,967

` 1 claim.` (ci. 1371-139) This invention relates to anew and improved automatic pistontypedischarge v alve, and more particularly to a quickacting power-operating discharge valve especially designed for use' in cori- 5 nection with thepumping mechanism used in a vacuum steam heating system of the; type disclosed in the patent to Dunham 1,644,114 granted october 4,1927. f i" f The pumping system to which this'invention is applied utilizes a hurling water circuit 4toproduce a vacuum in the heatingsystem and withdraw air and condensate therefrom. The pumping system has an inlet which communicates with the return pipe from the heating system,` and an outlet through which water 'forcedtd Lthe boiler or generator of the heating system. The pumping system maintains' a relatively low pressure or vacuum in the return pipe 1of the' heating' system so that air and condensate will be withdrawn therefrom, and a relativelyhigh pressureis maintained in the discharge pipe `so that Water can lbe forced out against thefboiler pressure. There is a vcut-oil valve in the discharge pipe which is normally closed but which is opened" by a-iioatcontrolled mechanism when a certain predetermined amount of waterhas'accumulated in the pumping system so that'the excess'water'will be forced back to vthe boiler. When'an ordinary type of valve is used at this pointgwh'ich is directly operated from `a float withinfthe tank or reservoir in which the Water accumulates, difficulties have been encountered owing to the valves becoming leaky either'from the deposits of foreign matter thereonorfrom'the valve seat beingffcut owing to the very low rate of speed at which the valve is lifted from `-its seat or. returned thereto.V

The present inventionl relates Yto-a new-"and improved form of discharge valve especially de"-4 signed for use vin aipumping system such'l as briefly described hereinabove.;V although I the valve' 'is' capable of other uses Themain cut-off valve is operated by la pair of opposed:fluid-pressure operated pistons which'force the valve quicklytosor from its seat. The main valve discisfor'medof a composition which is sufficiently hardto wear well but at the same timeis soft enoug'ltoenable any solid materials .to be embeddedihit when the valve is moved to closed position so that the valve will make a tight contact with its `seat despite the presence of foreign substances. (The valve `is alsov provided with a sleeve1 movable through the valve opening 'andrprovidedfwith' graduated openings in itsside Awalls so that the rate of flow through the valve opening will be gradually increasedbr Hdecreasedsof not i to cause water hammer when the movable valve member is opened or closed rapidly. A distributing valve directs a uid under pressure into one or the other of the cylinders in which the operatingpistons are slidable, at the same time exhausting the other cylinder so that a very quick and positive movementA of the cut-off valve is obtained. The distributing valve is operated from a iioat within the tank or reservoir through a lost motion connection.

Theprincipal object of this invention is provide animproved automatic discharge valve ofthe typeV briefly referred to hereinabove and disclosed` more in detail in the specifications which follow.

i Another object is to provide an improved for of piston-operated cut-off valve.

b Another object is to provide an improved form of movable member for the discharge valve which will seat tightly even if solid foreign matter interposed between the valvel and valve seat.

l Another object is to provide a movable valve member adapted to graduate the increase or decrease of ow through the valve opening wh the Valve is quickly opened or closed.

Another object is to provide improved hydraulic pressure means for opening and closing the valve withoutthe need of large float leverage.

may be fully opened or closed even though t change in' water level is slight and the floatleverage is small.V

`Another object is to provide a valve structure in'which the wearing parts areeasily accessible fo'r'inspection and renewal.

wAnother object is to provide a valve structure that is simple-and economical to manufacture, and will give long,vcontinuous and uninterrupted other objects and advantages of this invenu will be more apparent from'the following detailed description of `one approved form of apparatus constructed and operating according to the principlesof this invention.

In the accompanying drawings:

``Eig. 1 is an elevation showing the pumping mechanism `with the improved discharge valve and its'operating connections assembled therewith, i

2 is a longitudinal vertical central secti through the discharge valve.

Fig. 3 is a vertical section taken substantially on the line 3 3 of Fig. 2.

Fig. 4 is a horizontal section taken substantially on the line 4 4 of Fig. 2.

Fig. 5 is a perspective view of the movable valve and piston assembly.

Fig. 6 is a perspective view of one of the removable cylinders.

Referring l'rstztogFig. 1, the pumping mech-anism and exhausting system to which this invention is applied comprises a tank 1 partially filled with water, from the lower portion of which a pump 2 driven by motor BtWithdrawsi-water through intake pipe 4 and forces this water upwardly through the discharge 'T '5 .and jetexhauster 6 into the pipe 7 leading'back iritothe upper end of separator tank 1. This hurling water circuit produces a suctioninthefcasing of ejector 6 which draws in water and gases. through pipe 8, which may be the return pipe lea'ding from a vheating system. lThe gases fand condensate drawn in through pipe8 -arefcarrie.d-.along'yvith the hurling water through` discharge; pipe' '7 1 into the tank 1. :A one-Waycheck valve-.9:inthepipe 8 prevents the return of .'-any .of these tfluids throughpipe Sito the heating system. '.'Iheggases discharged,- into Vv.tank 11 are .vented v.to the atmosphere through'pipe 10 provided f-vvith Ionesway valve 11. n 4 v It will be apparent that the :amount .ofi'waterin the hurling Y, circuit *will be constantly :increased due to .the addition of condens-ate'fromf the; heating system so that ,thewater level.- intank -1 '(indicated'at l2) will rise andit is .gdesirablefto fdischarge part of this water, preferablygback tothe boiler of the heating-system. :Forthis purpose a discharge pipe 13; leadsi from .tl'ie T-.5` ofpump'1f2 throughacheck .valve 1.4. back to-.the boiler. A cut-ofi valve -.15 located in discharge Apipe .1-3 is normally .closed buta is: opened by. aoatezcontrolled mechanism Y when ythe-.water level :12 x in tank-L has risen to a predeterminedflocation .and :is again closed when-.the ,excesswaterhasrbeen- :discharged fromthe tank. The present-.invention relateseto an improved formof-.cut,off.valve 115 .andto the mechanism for operating.this-valvezwhentthe, float in .tank 1 -has reached certain :predetermined positions. ,Themproved discharge val-ve 1.5 will be.-more speciiically described. The .valve casing v16 lis formed `withan inlet ,port i 17 :leading to an upper chamberl, and an outlet,port .19,leading1from a-lower chamber 2C,` the chambers 1.8 andf20.- being separated by i a,` substantially horizontal-'partition 21 in which is .formed the vertical @valve opening. A cylindrical sleeve or bushing 22 ffitted within thisvalve opening is formedwith-an-upperfrounded valve seat. 23. rA restriction :plate 5:24, which may have a central aperture,25.of..any Adesired size, yis secured in. thez outlet port 19, so-as.toaadapt a, single. size of valve to Ta .plurality.of tdiiferent flowecapacities. v s

A valve cup or holder 26 is fitted against a shoulder 27 -onthepistonrod 28 -.which extends vertically through .the `valve `opening fand' charnbers18..and 20. A disc.29 of suitable-relatively soft compositionmaterial is held-.within'the cup 26 and is adapted to engagethev-a'lve fseat 23. A valve cup slidablewithin--the bushing 22-:comprisesahead 30.1'itted on thetpiston rodf237and held, inplace by nuts31-screwedon athreaded portion .of the .rod therebysecuringl in Eplace .the composition disc 29. This Valve cup is formed with a oylindricalskir-t,por-tion32 -,which I lts slidably within bushing 22 andis formedwithrdiverging cut-out portions or' notches 33. These openings 33 are so proportioned that as the valve is raised quickly to open position the flow of liquid through the valve opening from chamber 18 to chamber 20 will be gradually increased. In a similar manner the flow will be gradually cut off instead of suddenly cut off when the valve is quickly moved to closed position. .In this .way .water-hammer is prevented. "'.The flow through theavalve is completly cut off when the composition disc 29 is brought against the valve seat 23, and this disc .isformed of suiciently soft material so that any ssoliidforeignma'tter which may become lodged on the valve seat will be embedded within the lcomposition .discand not prevent a complete closingof'thevalve.

On the similar reduced end portions 34 and 34 ofpiston ro'd 128 r-aremounted similar upper and .lowerpistons each comprising a main disc 35 recessed to receive a jointless packing ring 36, agclanping disk .37 `to .fhold y.the packing ring L in place and nutss38x.threadedonthezend portionof thel rod to :hold the piston :assembly -in place. Obviously, a .'sol-id :piston A:could =.bev used -but .in such ica-se it :wouldfbewnecessaryto .use a split packing ,ring This .entire piston aand valve assembly is movable up1 anrldownlA as afsingle unit and is shown in perspective in Fig. ,5.

' The ,-'valve @casing ,"16v fis formed Awith :similar upwardlyand .downwardly proj ecting@ openeended cylindrical neekxportions 39;and'140 ea-chi of :which is Iclosedxby .-.a `similar removable vdished cap member, the i upper cap lbeingndesignated 241 f and the alower n one V42. These -capsfa-refheld in :place by;boltsi431screwed intofthefcasing .16. 'Itiwill be Sanna-rent that when rthese `caps are :in :place the fino-ving portions fof the :.valve -.assembly :are entirely-- enclosed so -that :no stuingboxes .are

necessary.

:The similar-hollow cylindrical liner.members;44 andf45 havebylindrical interior .openeendeldbores in which thedpistons;v are aslidablytted. .-Eachnf thefcylindrical linersi is provided withfan Vexterior annular iiange f or z collar 4'6 which iis 1 clamped; in an annular recess :.formed part'ly in the casing neck .-39 or `40 fand; partly :in the closure cap 1.141 orf42. vvvllhenthecapsgaresecuredrin place against annular gaskets 47, .theylindrical liners .are clampedin place.:andgatthefsametime :the assembly .is sealedto prevent :the .escape :of motive ud .between :the r.casing :and soaps. :A compression spring flcconnedbetweemthe;top.;of= .cap/41 and the top lof :thetupper .'piston ..serv es i to inormallyfholduthe movablepistonand.valvezassembly downward with :the valve. closed.

Separate upper aand `lower inlet iports- 49 fand 50 for fthe zmotive fluid .zare formed ;in .ione side Wall :of -:ca-sing 16, sand fpassages :5l ,and .52 ylead respectively-.fromtthesellortsnpwardlyfand downwardlyithroughzthemecks.9sandi4irespectively. The 1 ,upper `cap 141 ..is .formed -Lvvith ra :passage :f5.3 which ycommunicates :,at tione end n'with the ipassageil '.-inuthevialve :casing .,andleadstat. its. .other end.;into 'the :space'ii .above :the upper piston. The :lower :cap-'42 :is i formed nwith f a .f similar passage 55 "which forms. an extension of the casing passage; 52; andv leads into .the ;1ow.er.,chamber:156 beneath the ilower piste-n. .Supplyconduits15'7 and :58; connectfinto ithei ports 49 :.andforespectively. A l

:'Referring'fnow :.togfFig. 1,;-a l.closure plate 59 `is fitted overtfanopeningormedjn rione-:side: of .the upper.portion|;of|..tank 1.1and thiszplate is formed with r'a hollow f.outwardly tapering bracket extension 60, in:,theonter;portion.of-.which islhoused Cil a distributing valve 70, having a removable closure plate or head 74 secured in place by bolts 75. The ioat 62 which rests on the water in tank 1, is connected by stem 63 to the inner rotary element of the distributing valve.

A supply conduit 97 extends from some portion of the circulating system containing water under the high pressure developed by pump 2 and leads into a port 98 in the casing of thedistributing valve 70. Conduits 57 and 58 lead from outlet ports in the valve head 74 to the inlet ports 49 and 50, respectively, of the improved discharge valve (see Fig. 3). i

Let us assume now that the discharge valve 15 has just been closed after the excess liquid has been discharged from tank 1, thus lowering the float 62 to a predetermined minimum level so as to adjust the distributing valve 70 and connect high pressure supply pipe 98 with conduit 57. Water under high pressure will have passed through conduit 57 and valve passages 51 and 53 to the upper valve chamber 54, thus forcing down the piston assembly and closing the valve 29. At the same time, fluids in the lower valve chamber 56 have been discharged through valve passages 55 and 52 and conduit 58 which is now in communication through distributing valve 70 with the interior of tank 1.

As the liquid now gradually accumulates in tank 1, the water level 12 will be raised thus raising the iioat 62 and when a predetermined maximum liquid level is reached the distributing valve 7U will be adjusted to place supply conduit 98 in connection with conduit 58, and to connect conduit 57 with the space under atmospheric pressure in tank 1. The piston assembly will now be `raised quickly to fully open the discharge valve and permit the pump 2 to discharge the surplus water from tank l through pipe 13.

The closing movement of the valve, as first de scribed, will also take place quite quickly, but the flow of water through the valve will be more gradually cut oi, due to the gradual closing of the tapered openings 33 in the cylindrical valve skirt 32, thus preventing water hammer.

It will be noted that the effective diameters of the upper and lower pistons and of the main l valve opening are substantially equal so that the iiuid pressures exerted on these members from the main valve chambers 18 and 20 will substantially balance one another. The valve is thus held closed mainly by the expansion spring 48, although a somewhat higher pressure must exist in chamber 18 than in chamber 20 since this excess pressure is necessary in order to force liquid to the boiler. This pressure differential also tends to hold the valve closed. Of course, when the space beyond one piston is exhausted and liquid under pump pressure is admitted to the space beyond the other piston, this balance of forces is destroyed so that the piston assembly will be moved quickly in the appropriate direction.

By removing one or both of the valve heads 41 and 42 of the main discharge valve, the cylinders and valve assembly can be withdrawn and all parts of the valve are readily accessible.

For convenience in identifying the parts, the discharge valve has been -described as if it were positioned as shown in the drawings, the pistons, cylinders, heads, etc. being described as upper and lower with relation to this positioning of the valve. It is to be understood that the valve could be positioned sidewiseor inverted without materially affecting its operation as hereinabove described.

I claim:

A piston-type discharge valve comprising a casing enclosing upper and lower chambers with which communicate inlet and outlet ports Yrespectively and an intermediate substantially horizontal partition formed with a valve opening and a valve seat surrounding the opening at the inlet side, a piston rod projecting vertically in both directions through the valve opening, a valve member iixed to the rod intermediate its length and adapted to close the valve opening, upper and lower pistons mounted on the respective end portions of the rod, there being openings in the top and bottom of the casing coaxial with the valve opening, similar dished caps for closing these openings, duplicate upper and lower open-ended hollow cylinders in which the pistons slidably fit, each lcylinder having an outstanding annular collar which is clamped in place between the casing and cap, there being ducts for a pressure iiuid in the side walls of the caps and the casing which communicate when the caps are in position, the duct in each cap leading directly from the space beyond the adjacent 4piston to the adjacent duct in the casing, the other end of each casing duct being provided with an inlet port through which a pressure fluid isdirected from outside the valve casing to open or close the valve.

CLAYTON A. DUNHAM. 

